1. Field of the Invention
The present invention relates generally to a vehicle such as bicycle or tricycle, and more particularly, to a vehicle's steering bearing assembly, which has a compact structure that is easy to manufacture and maintain.
2. Description of the Related Art
A conventional bicycle's steering bearing assembly 1 (as shown in FIG. 7) is provided between the bicycle frame (not shown) and the steering tube 4 for enabling the steering tube 4 to be rotated relative to the bicycle frame. The bicycle frame has a head tube 5 at the front side for accommodating the steering tube 4. The head tube 5 has a top inside annular groove 6 and a bottom inside annular groove 7 that accommodate a top bearing 8 and a bottom bearing 9 respectively. The top inside annular groove 6 has a tapered face 10 at the bottom side for the contact of the tapered face 11 on the outer side of the top bearing 8. The top bearing 8 also has a tapered face 12 on the inside for bearing the tapered face 14 of a compressing member 13. A cap 15 holds down the compressing member 13 between the top bearing 8 and the steering tube 4. Thus, the steering tube 4 can be rotated relative to the head tube 5 (i.e., the bicycle frame).
In the aforesaid design, the processing precision requirement for the top inside annular groove 6 and bottom inside annular groove 7 is critical. For example, if the depth of the tapered face 10 of the top inside annular groove 6 is insufficient, the top bearing 8 will protrude over the head tube 5, thereby allowing entering of dust and water through the gap in between the cap 15 and the head tube 5. On the contrary, excessive depth of the tapered face 10 of the top inside annular groove 6 causes the top bearing 8 to sink in the head tube 5, thereby resulting in interference between the cap 15 and the head tube 5. Therefore, the aforesaid conventional method cannot improve the yielding rate; in consequence the manufacturing cost cannot be effectively reduced.
Further, the head tube 5 wears after a long use. When the top inside annular groove 6 or bottom inside annular groove 7 is deformed, the repair work is complicated and requires much time.